The railways are being modernized because since the disintegration of Yugoslavia there have been hardly any investment in railway infrastructure. Many important routes are not electrified and are only single track traffic around 'bends'. Major improvements are being underway especially on routes that can be best economicaly exploited for cargo transport. A result of this has been an increase in the maximum speed on the railway line on the Pan-European Corridor X, from the Slovenian border via Zagreb, Novska and Vinkovci to the Serbian border. In places the line's speed limit has been raised from 80 km/h to 120 km/h, and plans have been made to raise this further to 160 km/h on certain sections.
The railway line of the Pan-European Corridor Vb, from the Hungarian border via Koprivnica, Zagreb and Karlovac to the seaport of Rijeka had slow section through Gorski Kotar, which underwent a major overhaul in 2014.
The railway line of the Pan-European Corridor Vc, from the Hungarian border via Beli Manastir, Osijek, Đakovo or Vinkovci, Slavonski Šamac, to the Bosnian border, is also being modernised, the aim is to allow speeds of up to 160 km/h along the entire length.